Test Cross
A cross used to determine the genotype of an individual with a dominant phenotype by crossing it with a homozygous recessive parent.
What is Test Cross?
A cross between an individual exhibiting a dominant trait and a homozygous recessive individual to determine the genotype of the former.
Key points
- Define a test cross.
- Explain the procedure of a test cross.
- Interpret the results of a test cross to determine an unknown genotype.
- Differentiate a test cross from other types of genetic crosses.
Common exam trap
Using a homozygous dominant or heterozygous individual as the tester parent.
Definitions
- Term
Test Cross
- Meaning
A cross between an individual exhibiting a dominant trait and a homozygous recessive individual to determine the genotype of the former.
- Term
Homozygous Recessive
- Meaning
An individual having two identical recessive alleles for a particular gene (e.g., 'tt').
Learning objectives
Define a test cross.
Explain the procedure of a test cross.
Interpret the results of a test cross to determine an unknown genotype.
Differentiate a test cross from other types of genetic crosses.
Prerequisites
Understanding of Mendelian genetics
Concepts of dominant and recessive alleles
Homozygous and heterozygous genotypes
Monohybrid cross
Common mistakes
Using a homozygous dominant or heterozygous individual as the tester parent.
Incorrectly interpreting the offspring phenotypic ratios.
Confusing test cross with back cross or reciprocal cross.
Keywords
Test cross
Genotype determination
Dominant phenotype
Homozygous recessive
Heterozygous
Homozygous dominant
Mendelian genetics
Punnett square
Practice preview
In a test cross, if the individual with the dominant phenotype is heterozygous (e.g., Tt), what will be the phenotypic ratio of the offspring?…
easy
What is the primary purpose of a test cross?…
easy
Which of the following is always used as the parent with the unknown genotype in a test cross?…
easy